Abrasive positioning means for abrading machines



Man]: 31, 1953 R. 'r. OSMAN 2,632,982

ABRASIVE POSITIONING MEANS FOR ABRADING MACHINES Filed Sept. 14, 1950 INVENTOR.

Patentecl Mar. 31, 1953 ABRASIVE POSITIONING 'MEAN S FOR ABRADING MACHINE S Ralph T.0sman, Whitefish Bay, Wis.

Application September 14,1950, Serial'No. 184,734

4 Claims. (01. 51189) This "invention relates to surface abrading apparatus andmore particularly resides "in that type of machine in which an abrasive sheet is held by 'tensioned gripping means to a working shoe to which is imparted either a gyratory or oscillatory motion and in which the gripping means may be removed from and be entirely independent of the working shoe with which it cooperates.

In the use of sanding,polishing orother abrading machines of the gyratory or oscillatory type it is desirable to be able to abrade the entire surface being worked without marring or otherwise injuring portions of the work piece rising upwardly from the surface at corners, etc. To accomplish this objective, protruding metallic or other non-resilient portions have been eliminated from the boots of some machines and the exterior of these boots have been formed of a resilient material that may act to cushion abusive impact with shoulders or offsets in the work piece. To accomplish this end, clamping means for placing and positioning the abrasive sheets, such as sandpaper or emery cloth, on the machine have been eliminated and in lieu thereof adhesively attached abrasive sheets have beenemployed.

Sandpaper, emery cloth and other abrasive sheeting wears and must consequently be replaced at intervals. To replace the abrasive it is desirable that a quickly and easily performed operation be made. Adhesive attachment of the abrasive sheeting because of the difliculty of releasing the worn sheet and the delay attendant upon setting of any liquid adhesive employed, is not as rapid and convenient as may be desired. When the work is flat or for any other reason does .not require abrading of edges and corners adjacent offset portions of the work piece resort to an abrasive sheet held in position by a clamp may be deemed more convenient. Special advantages therefore would be possessed by an abrading machine which could employ either adhesively attached or clamp held abrasive sheets and in which the destructive metallic parts of the clamping means could be removedfrom the range of destructive action to permit cushioned portions extending about the boot of the machine to perform their intended protection action whenever an adhesive backed abrasive sheet is used in conjunction therewith.

It is therefore an object of this invention to provide a clamping means for maintaining and positioning. an abrasive sheet on the shoe of an abrading machine without adhesive but which ay be w olly removed om the abrading machine when adhesive attachment of an abrading sheet is desired.

It is another object of this invention to provide a clamping means which is simple in operation and which may be quickly and easily operated and which will function well on a shoe having cushioned margins.

It is a further object of this invention to provide a clamping means embodying the foregoing objects which acts upon the abrasive so as to stretch and extend the same over the working shoe of the machine .as it is being attached thereto.

These and other objects will appear in the description to follow. In the description reference is made to the accompanying drawing which forms a part hereof and in which there is shown by way of illustration and not of limitation one form of this invention.

In the drawings:

Fig. 1 is a side view in elevation of an abrading machine to which an abrasive sheet is aflixed by one form of clamping means constructed in accordance with this invention,

Fig. 2 is a view in perspective of the clamp only, shown in Fig. 1,

Fig. 3 is a fragmentary expanded view in perspective of the abrading machine depicted in Fig. 1 showing an abrasive sheet and the clamp in the position relative to the shoe of the machine which is assumed just prior to clamping the sheet to the shoe.

Referring now to the drawings, there is shown in Fig. 1 an abrading or sanding machine having an upper part of known construction that imparts a gyratory or oscillatory movement to a shoe. The machine shown is provided with a frame I to which is attached a housing for a driving motor 2. Secured to the motor 2 are hand grips 3 and 4. A power lead 5 for the motor 2 passes through the large hand grip 3. Attached to and extending below the frame I is a boxlike boot 6 composed of a flexible resilient material such as stiff moulded rubber or other similar composition having properties resembling tire tread stock. integrally joined with and forming a bottom for the flexible boot 6 is a shoe portion 1. The shoe 1 is also composed of stiif moulded rubber composition or other similar yieldable resilient material. Within the boot 5 above the shoe 1 are parts, not shown, of known construction that are driven by the motor 2 and which impart a recurrent motion to the shoe 1.

The two lengthwise sides of the shoe 1 extend slightly outwardly from the boot 6 to form yieldable side margin portions 8. The ends 9 of the shoe 1, also of yieldable material, each have an abutment ledge or trough III extending horizontally from the full length thereof. The bottom of the shoe I presents a' substantially fiat working surface II which may be moved in relation to a work piece that is to be abraded or sanded and to which is imparted the recurrent motion. To the flat working surface II is attached an abrasive sheet I2 such as sandpaper or emery cloth, which extends across the entire area of the flat working surface I I and at the two oppositely disposed ends 9 folds upwardly around the edges is formed by the junction of the flat working surface II and the ends 9. The sheet I2 also folds into the troughs I at both ends and is held in such position by two clamp rollers I4, one disposed in each of the troughs I 9, that press inwardly upon the sheet I2.

The clamp rollers l4, formed preferably of tubing, are held in position by a pair of side links preferably in the form of a stiff resilient clamping bail I which connects the rollers I4 to one another as is more clearly shown in Fig. 2. Two longitudinal runs I6 of the bail wire I5 extend substantially the full distance between the rollers I4. At each of the ends of these longitudinal runs I6 an elbow I! is presented by the forming of a downwardly offset portion I8 that connects at its lower end to its associated roller I4 by turning into the tubing of which the roller I4 is formed. By providing a single strand of wire in the form of a closed roughly rectangular loop for the bail I5 a unitary clamp is formed that may be completely disengaged from the abrading machine proper. The bail I5 may also, if desired, be made of two separate strands each secured to the rollers I 4 in suitable manner. The bail I5 is dimensioned when unstressed to position the rollers I4 at a distance from one another less than the distance between the troughs I II and whenever a greater separation of the rollers I4 occurs the bail I5 will act strongly to urge the rollers toward one another.

Whenever it is desired to apply the abrasive sheet I2 to the abrading machine it is placed with the back thereof facing the working surface II, as shown in Fig. 3. The ends of the abrasive sheet I2 will extend outward and beyond the edges IS. The rollers l4 are then manually brought upward so as to contact the abrasive sheet I2 and press it between the rollers I4 and the surface II. As the rollers I4 are then extended outwardly along the surface II and pressed upwardly and about edges I3 a rolling motion occurs which tends to extend the abrasive sheet I2 longitudinally so as to render the same taut. As the rollers I4 are passed over the edges I3 and upwardly across the ends 9 they engage the troughs I0. This manual operation of the rollers I4 brings the spring function of the clamping bail I5 into play. The offset portions I 8 acting at the elbows I'I toward the ends of the abrading machine induce a resilient bowing of the longitudinal runs l6 as is shown in Fig. 1. The resilience of the bail wire I5 under the bowing action urges rollers I4 into pressing contact with the abrasive sheet I2 and troughs II]. By reason of the bail I5 holding the rollers I4 apart from one another at a desired predetermined distance when the clamp is free of the shoe I an easily performed mounting operation for the abrasive is had. Further, the offset construction of the bail I 5 positions it well ab ve t surface to be worked.

When desired the clamping bail I5 and rollers I4 may be completely removed and put aside and an adhesively attached abrasive sheet utilized. The margins 8 and ends 9 then provide a cushioned portion to protect offsets, corners and shoulders of a work piece from the impact damage which might otherwise ensue from contact with the rollers I4.

I claim:

1. In an abrading machine a shoe having a working surface adapted to be moved in respect with a work piece to be worked and having upwardly extending end portions each with an abutment ledge extending substantially lengthwise thereof, oppositely acting clamping members adapted to engage in mating relationship with the abutment ledges of said end portions, and side links in connecting relationship to said clamping members disposed above said flat working surface comprising a pair of resilient bail wires each having a substantially straight longitudinal run of a length approximating the distance between said abutment ledges and having a downwardly extending offset portion at each end of the longitudinal run engaging an end of one of said clamping members and adapted to be resiliently distorted transversely of said longitudinal run to permit limited separation of said clamping members and to urge said clamping members toward one another into pressing contact with the abutment ledges of said end portions, said clamping members and said side links forming a unitary whole detachable from said shoe.

2. An abrading machine in accordance with claim 1 wherein said abutment ledges comprise lengthwise disposed troughs in said end portions and said clamping members consist of a pair of rollers.

3. In an abrading machine a shoe having a rectangular working surface adapted to be moved in respect with a surface of a work piece to be worked and having a pair of end portions adjacent to said flat rectangular working surface of said shoe, each of said end portions having a recessed trough extending parallel to said flat rectangular working surface, a pair of roller clamps substantially the length of the troughs of said end portions adapted to engage in mating relationship with the troughs of said end portions, a first resilient bail wire having a substantially straight longitudinal run of a length approximating the distance between said troughs and having downwardly extending legs at each end of said longitudinal run connected at the lower ends of said legs to one end of one of said rollers and to the respective end of the other of said rollers disposed above said flat rectangular working surface, and a second resilient bail wire similar to said first resilient bail wire connected to the other ends of said rollers disposed above said flat rectangular working surface, said resilient bail wires being adapted to be resiliently distorted transversely of said longitudinal runs to permit limited separation of said rollers to pass the same over said end portions of said shoe into engagement with said troughs and to urge said rollers toward one another to apply clamping pressure to the ends of an abrading sheet disposed in said troughs.

4. In an abrading machine a shoe having a rectangular working surface adapted to be moved in respect with a surface of a work piece tobe worked and having a pair of end portions adjacent to said fiat rectangular working surface,

each of said end portions having a recessed trough extending parallel to said fiat rectangular working surface, a pair of roller clamps substantially the length of the troughs of said end portions and adapted to engage in mating relationship with the troughs of said end portions, and a resilient bail wire extending from one end of one of said rollers to the respective end of the other of said rollers and extending in like manner between the other ends of said rollers, said ball wire being formed with offset portions rising upwardly from each roller and substantially straight longitudinally extending portions joining the upper ends of said offset portions, said resilient bail wire being adapted to be resiliently distorted transversely to said longitudinal extending portions to permit separation of said rollers to pass the same over said end portions REFERENCES CITED The followinglreferences are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 763,605 Hepp June 28, 1904 15 2,204,486 George June 11, 1940 2,475,476 Champayne July 5, 1949 

